[postgis-users] Bounding Box Query

[iheanyi Okeh]

Hi Tyler,
This is the first time I am getting a response from member listers.
Thanks for inquiring.,
Can you repost your response, please?


>From: Tyler Mitchell <TMitchell at lignum.com>
>Reply-To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
>To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
>CC: 
>postgis-users at postgis.refractions.net,postgis-users-bounces at postgis.refractions.net
>Subject: Re: [postgis-users] Bounding Box Query
>Date: Mon, 29 Mar 2004 08:36:30 -0800
>
>Are you getting email from the list okay?  A couple of us had responded a
>week or so ago...
>
>postgis-users-bounces at postgis.refractions.net wrote on 03/29/2004 05:51:08
>AM:
>
> > I had posted this question here before but didn't get any response.
> > I was encouraged to try it again.
> >
> > I have a query that retrieves an address closest to a point given an x/y
>
> > coordinate pair.
> >
> > This is that query:
> >
> > SELECT str_num || ' ' || name as full_address,
> >    distance(the_geom,'POINT(2227284.1963667543
> > 1435389.6730164126)'::geometry) as dist
> >    FROM address
> > ORDER BY dist limit 1
> >
> > The above query works as far as returning the closest address to a point
>
> > based on x/y coordinate pair.
> >
> > Hower, performance is really bad as it takes quite sometime for this
>query
> > to retrieve a record.
> >
> > I have a about bounding boxes or overlap operator (&&) as a means of
> > improving performance.
> >
> > I don't quite understand it how works.
> > For instance, given the below query (which doesn't work by the way),
> >
> > SELECT str_num || ' ' || name as full_address,
> >    distance(the_geom,'POINT(2227284.1963667543
> > 1435389.6730164126)'::geometry) as dist
> >    FROM address
> >    WHERE the_geom && 'BOX3D(90900 190900, 100100 200100)'::box3d
> >    AND distance( the_geom( 'POINT(2227284.1963667543
>1435389.6730164126)',
> > -1 ) ) < 100
> > ORDER BY dist limit 1
> >
> > My questions are:
> > 1, how are the arguments in bo3d shown below generated? I just filled in
>
> > those numbers without knowing where they come from or how they are
> > generated.
> >
> >    WHERE the_geom && 'BOX3D(90900 190900, 100100 200100)'::box3d
> >    AND distance( the_geom( 'POINT(2227284.1963667543
>1435389.6730164126)',
> > -1 ) ) < 100
> >
> > 2, how can I apply the information on question 1 to with the query above
>
> > (the one indicated as a working code)?
> >
> > All research I have done so far have not helped me.
> > Your assistance is greatly appreciated.
> >
> > _________________________________________________________________
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